The present invention relates to systems for retrieving information from archival storage and is more particularly directed to systems for retrieving data from print data streams.
The problem addressed by the present invention is illustrated by the familiar bank statement that every bank account holder receives every month. Banks are obligated to keep archival copies of all statements typically for a period of years, and many banks plan on holding archival copies much longer. An individual bank will generally have many thousands of account holders to whom it sends periodic statements. As a result, the bank's archives hold an extremely large number of statements.
The archives have traditionally been maintained on microfilm. More recently, optical disk systems have been devised for long-term archival storage. The microfilm stores a reduced photographic copy of the printed bank statement whereas the optical disk stores the coded information that was sent to the printer that printed the statement in the first instance.
When the archival records are kept on microfilm, whole statements are retrieved by reel and frame number (or fiche and frame number if micro fiche is used), and the microfilm is often coded with blip codes permitting specified statements or groups of statements to be located and retrieved automatically. In optical disk storage systems, a separate index database is maintained for retrieving statements from the optical disk. The computer searches the index database for statements cross indexed to a selected characteristic index field or fields such as the account number field to determine what to retrieve from the optical disk. Generally, special search and retrieval software has to be written to search the coded statement information for the desired characteristic index, and the desired index information has to be hard-coded into the software routine in advance. In addition, the software routine has to know the particular type of printer that was used so as to take into account the manner in which the desired characteristic will be encoded on the disk. The search and retrieval software generally has to be revised when the layout of the bank statements is changed or new fields are introduced into the bank statements. This requires the services of a highly trained computer programmer, which can be expensive, time-consuming and inconvenient just to bring into effect a simple revision in the form of a bank statement.